Yovanovitch lied under oath, then that the end of her claim.
She testified against because she was laid off. Laid off because her loyalty was with the Obama administration, not to the US government. She was appointed during the Obama administration in 2016.
Concerning her lay off, the president has the right to choose staff personnel under his administration.
Technically Trump can fire anyone he wants whether Democrats like it or not!!!! He doesn't need a reason,especially if she Yovanovitch worked for obama Administration!!!!!!